Alms Tax: Age Requirements for Sheep and Goats Given as Zakat

Practical Laws of Islam as per the teachings of Ayatullah Sistani

Ruling 1932

If a person gives one sheep as zakat, then based on obligatory precaution, it must be at least in its second year; and if one gives a goat, then as an obligatory precaution, it must be in its third year.

-Ayatullah Sistani, Practical Laws of Islam, Alms Tax (Zakat)